eventtarget.js

function eventTarget(o) {
    const {port1} = new MessageChannel();
    o.dispatchEvent = port1.dispatchEvent.bind(port1);
    o.addEventListener = port1.addEventListener.bind(port1);
}

// Usage:

let myObj = { /* ... */ };
eventTarget(myObj);
myObj.addEventListener('custom-event', event => console.log(event));
myObj.dispatchEvent(
    new CustomEvent('custom-event', {detail: 'some important detail'})
);